This is Florian, our third organizer.

So the people asked me to say two things first.

It seems that many people didn't get their lunch bags, especially on Saturday.

So if you don't want lunch bags, it would be better just to say a little more.

I think there were also 20 bags that you put in one of their bags on this weekend.

And also, please return the hiking maps that you took for the weekend,

because I think they need them and they will give them back for the next week.

I have an announcement. We are trying to videotap the lectures.

And so before each lecture, I will actually volunteer among the students

to make sure that we have a cameraman.

The duties of the cameraman are not very challenging.

It's just that the speaker actually starts to say something on the legboard.

You move the camera.

Okay, that's fine.

So it's exciting to have as our next speaker, Nervis Moumoua.

Nervis is a leading experimentalist in gravitational wave detection and optical mechanics.

And I'm delighted to be getting another introduction to gravity wave detection.

When I was a confused postdoc in atomic physics many, many years ago,

Nervis is actually the first person who provided me with my real introduction to working on atomic mechanics.

So thanks again. So hi everybody.

I want to thank Jack and Florian for having me here.

You might not thank them though, because they gave me the task of telling you about gravitational wave detectors.

And that's quite cool because I love them. I've been working on them for almost 20 years.

I'm an experimentalist. But on the other hand, there are going to be times when I will force you to deviate from your comfort zone.

So in today's lecture, for example, I'm going to tell you a little bit about general relativity. Imagine.

So, okay, so that's all for the disclaimer. If you don't like what you hear, it's their fault, not mine.

Okay, and the next thing I want to say is here is the outline of what the lectures are going to be.

So today's lecture, I'm going to give three lectures. Today's lecture is going to be on gravitational wave basics.

And that's where you'll encounter most of the general relativity and astrophysics.

Because in ultimately gravitational wave detectors, even though we myself included them as the original grandparent of all of the mechanics experiments,

ultimately they are an astrophysics instrument. So we have to grapple with the idea that that's really what we're after.

So I'm going to talk a lot about the astrophysics. But then in today's lecture, depending on how far you look at it,

I want to say just that you need to interact as much as you like. I don't really have an agenda.

Just some things will fall right into place as we talk too much. That's fine.

So I'll talk about the interferometers that we use for gravitational detectors. And I'll talk about just the basic idea to real actual realization.

So I'll say again, I'm an experimentist. And so all my lectures will be very experiment-heavy.

Now let me say something else about that for those of you who are already worried.

So I'm sharing a week with Ash Clark and Matthew Chan, two outstanding theorists.

And what that's allowed me to do is to really free myself of having to tell you much about the theory.

So all the theoretical stuff they will cover. And we've talked a little bit about it.

There will be some things that overlap and some that don't. So if you're worried that this doesn't have enough rigor, fear not. It's coming.

And then finally I'll end today's lecture, I hope, with everything we've done with these gravitational detectors in the first generation.

My second lecture will be second-generation detectors. And I'll say it right now.

So the second generation of detectors for the US, for the line of detectors. We start our first observing run in about two weeks.

And so it's a very exciting dance. I'll tell you what's been going on there, what are the key technologies, what are the major challenges.

And then finally, in my third lecture, I will dig really deep into quantum technologies.

The things that you folks mostly love the most of all of these, say you have to wait for your third lecture for.

But there'll be plenty in between. So that's sort of the outline of what's happening.

You notice my list for my lecture one was much longer than my list for my lecture two and three because I'm still kind of thinking through what I'm going to be talking about.

So it's not very well defined. So all talks about gravitational wave detection, you heard from David there.